A vacuum cleaner is an electrically powered, mechanical appliance utilized for the dry removal of dust and loose dirt from carpets, rugs, fabrics and other surfaces. Vacuum cleaners have been widely utilized for years in domestic and industrial cleaning applications.
In operation, a pressure drop is utilized to force air entrained with loose dirt and dust into the nozzle of the vacuum cleaner. The dust and dirt laden air is then drawn through a bag or dirt cup which traps and retains the dirt. The air is then exhausted by electric fan through an additional filter to remove relatively fine particles. It is this fan that provides the air pressure drop or vacuum that provides the cleaning action.
Airflow velocity and placement are the key parameters in determining the cleaning efficiency provided by the air drawn into the vacuum cleaner. A standard floor nozzle N for an upright or canister vacuum cleaner draws air under its entire perimeter and across its relatively large footprint area (see prior art design shown in FIG. 1). Airflow velocity V is minimal over most of this area, increasing gradually toward the mouth of the suction tube T, where it is maximized. Moreover, air, as a flow medium, follows the path of least resistance, and beyond the lower edge of the nozzle, will travel across the upper surface of the carpet. Hence, embedded residue is unaffected by airflow alone and deep carpet cleanability must rely almost exclusively on agitator performance. Stated another way, standard floor nozzles of the type illustrated in FIG. 1 fail to focus the airflow at the point where it is needed to provide deep cleaning action of the nap of a carpet or rug.
Long ago an attempt was made to focus airflow to provide better cleaning efficiency. Specifically, U.S. Pat. No. 1,601,774 to Scheffer describes a vacuum tool having a hollow cylinder formed with a plurality of suction apertures. The tool also includes a channel member formed with hollow trunnion ends which communicate with the legs of a tubular yoke via holes. Bearings mounted on each trunnion end secure within each end of the hollow roller. Thus, the roller may freely rotate about the channel member. In use, air is drawn through the apertures in the cylinder, the holes in the yoke and the handle.
Unfortunately, the vacuum cleaner tool disclosed in the Scheffer patent is only effective to focus the suction air stream along the upper ends of the nap and the surface of the rug or carpet. The Scheffer device fails to spread the nap of the rug or carpet to provide the desired deep cleaning at the base of the carpet and the bottom section of the nap. The present invention relates to an apparatus and method that provides true deep cleaning action. The apparatus and method of the present invention both spread the nap of the carpet in order to expose dirt and debris adjacent the base of the nap and simultaneously focus the suction airflow at the same location in order to provide greatly enhanced cleaning action heretofore unknown in the floor care cleaning industry.